Fogged,direct-positive silver halide emulsion containing a thallium salt and a dye containing a cyclo-heptatriene ring

ABSTRACT

A DIRECT REVERSAL PHOTOGRAPHIC SENSITIVE MATERIAL WHICH COMPRISES A PHOTOGRAPHIC EMULSION CONTAINING SILVER HALIDE PARTICLES THEREIN, AT LEAST ONE DYE REPRESENTED BY THE FORMULA (1)   R-N&lt;(=(CH-CH)M=C(-)-Z2-)-L2-L1-C&lt;(-CO-Z1-CH(-)-C(-)=)(-Z-)   (X(-))N   WHEREIN Z, Z1, Z2, R, L2, L2, X, N AND N ARE AS DEFINED HEREINAFTER AND A THALLIUM SALT, SAID THALLIUM SALT BEING ADDED TO SAID EMULSION DURING FORMATION OF SAID SILVER HALIDE PARTICLES, DURING PHSICAL RIPENING OF SAID EMULSION, OR DURING FORMATION OF SAID SILVER HALIDE PARTICLES AND DURING PHTSICAL RIPENING OF SAID EMULSION, IS DISCLOSED.

United States Patent Int. Cl. G03c1/28, 1/36 US. Cl. 96-101 13 Claims ABSTRACT OF THE DISCLOSURE A direct reversal photographic sensitive material which comprises a photographic emulsion containing silver halide particles therein, at least one dye represented by the formula (1) wherein Z, Z Z R, L L X, m and n are as defined hereinafter and a thallium salt, said thallium salt being added to said emulsion during formation of said silver 3,823,018 Patented July 9, 1974 ice formed is superposed on the positive image and thus the exposure latitute is lowered considerably.

An object of the present invention is to remove such disadvantages and to provide silver halide direct reversal 5 photographic sensitive materials which have a wide exposure latitude, a high spectral sensitizing elfect and a high sensitivity.

SUMMARY OF THE INVENTION The above-described object can be attained by using thallium during the formation of the silver halide and/or during the physical ripening, and by adding additionally at least a dye represented by the following formula.

In the formula, Z represents the group of atoms necessary to form a cycloheptatriene ring which may be substituted or unsubstituted, 2, represents -0 or NH--, and Z represents the group of atoms necessary to form a 5 or -6 membered heterocyclic nucleus, R represents a substitutedor unsubstituted alkyl group, L and L each halide particles, during physical ripening of said emulsion, or during formation of said silver halide particles and during physical ripening of said emulsion, is disclosed.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to silver halide direct reversal photographic sensitive materials. In greater detail, the present invention relates to silver halide direct reversal photographic sensitive material for forming direct positive images having a high reversal sensitivity and a wide exposure latitude by using only one exposure and one development. The term silver halide direct reversal photographic sensitive material means a photographic sensitive material in which the optical density after development decreases as the amount of exposure applied thereto increases.

2. Description of the Prior Art It is well known that the reversal sensitivity increases remarkably in the production of such photographic sensitive materials when a desensitizer is added to previously fogged emulsions. As the desensitizer, organic compounds such as pinakryptol yellow and pinacryptol green and compounds containing metals of Group VIII of the periodic table, such as rhodium compounds and iridium compounds (see US. Pat. No. 2,717,833) are known. Further, it is known that high contract direct reversal photographic sensitive materials having much higher sensitivity can be produced by adding thallium salts and/ or mercury salts to the above emulsions (see British Pat. No. 1,203,744). However, if the direct reversal photographic sensitive materials having a high sensitivity are produced by the process described in British Pat. No. 1,203,744, a phenomenon known generally as the rereversal phenomenon is caused, namely, a phenomenon that as the exposure abount increases the optical density after development reaches a minimum value and then the density increases. Therefore, the negative image represents a methine group or L may form a methylene chain by linking with R,X represents an anion and m and n each represents 0 or 1.

DETAILED DESCRIPTION OF THE INVENTION As described above, Z represents the group of atoms necessary to form a cycloheptatriene ring. Z may be substituted by substituents known in troponoid compounds, for example, lower alkyl groups (e.g., having.

1 to 4 carbon atoms such as methyl, ethyl, isopropyl,

etc.), halogen atoms (such as chlorine atoms or bromine atoms, etc.), alkoxy groups (such as methoxy groups, etc.) and aryl groups (such as phenyl, tolyl, nitrophenyl, naphthyl, etc.).

Z as described, represents the group of atoms necessary to form a 5- or 6-member heterocyclic nucleus conventionally known in cyanine dyes. The heterocyclic.

nucleus formed by Z includes, for example, an oxazoline nucleus, an oxazole nucleus, a benzoxazole nucleus, a

T naphthoxazole nucleus, a thiazoline nucleus, a thiazole nucleus, a benzothiazole nucleus, a naphthothiazole nucleus, a selenazole nucleus, a benzoselenazole nucleus, a naphthoselenazole nucleus, a 2-pyridine nucleus, .a 4- pyridine nucleus, a 2-quinoline nucleus, a 4-quinoline nucleus, an imidazole nucleus, a benzoimidazole nucleus, 21 naphthoimidazole nucleus, an indolenine nucleus or an imidazole [4, 5, 6]-quinoxaline nucleus etc. The Z heterocyclic nucleus may be substituted by known substituents in the field ofsensitizing dyes such as an alkyl group (methyl, ethyl, etc.), an aryl group (such as phenyl, naphthyl, etc.), a hydroxyl group, an alkoxy group (such as methoxy, ethoxy, etc.), a halogen atom (such as chlorine, bromine, iodine, fluorine), and the like.

R represents an alkyl group or a substituted alkyl group. Preferably R is a lower alkyl group or substituted lower alkyl group containing from'one to six carbon atoms. Suitable examples are methyl, ethyl, propyl, isopropyl, butyl, hexyl, cyclohexyl, B-hydroxyethyl, 'y-hy droxypropyl, fl-methoxyethyl, fl-carboxyethyl, 'y-carboxypropyl, B-carboxybutyl, B-sulfoethyl, 'y-sulfopropyl, 'y-sulfobutyl, fi-sulfobutyl, fl-sulfatoethyl, 'y-sulfatobutyl, B-acetoxyethyl, 'y-acetoxypropyl, fl-methoxycarbonylethyl, 'yethoxycarbonylpropyl, vinylmethyl, benzyl, phenethyl, pcarboxybenzyl, p-sulfobenzyl, p-carboxyphenethyl, p-sulfophenethyl etc. It may be substituted by known substituents in the field of sensitizing dyes.

Dye H Dye I Dye K Dye L Dye M Dye N CH=CH 1 CH= js\ 1- o CH=CH CH- cmQ-sor The dyes represented by the formula (1) used in the present invention can be synthesized by the process set forth in U.S. Patent Application Ser. No. 90,070, filed Nov. 16, 1970, now U.S. Pat. 3,687,674.

Suitable thallium salts are the water soluble salts such as thallium thiosulfate, thallium nitrate, thallium sulfate, thallium carbonate, thallium, nitrite, and thallium hydroxide. Thallium nitrate and thallium sulfate are preferably used in the present invention.

The silver halide photographic emulsions to which the thallium salts can be added are those prepared by dispersing a silver halide, such as, silver bromochloride, silver bromide, silver iodobromide, silver iodochloride or silver iodobromochloride in gelatin or a hydrophilic organic colloid such as polyvinyl alcohol, polyvinyl pyrrolidone, and the like, as the protective colloid, in which the present invention is characterized by adding the abovedescribed thallium salts during the emulsification of the silver halide at the step of preparing the emulsion or during physical ripening. The amount of the thallium salt to be added is from IX mol to 1x 10- mol and preferably from 1x10" to 1 10- mols as thallium per mol of silver halide. The amount of the dyes represented by the formula (1) added together with the thallium salts is from 10 mg. to 1 g. and preferably from 100 to 500 mg. per a mol of silver halide although the amount depends upon the kind of dye and the emulsion which is used. Generally, from 50 to 400 g. of silver halide per kg. of the emulsion are used.

Although, the addition of these dyes can be carried out during any step of preparation of the emulsion, the most preferable results are obtainable when the dye is added after the conclusion of the formation of fog nuclei or just before the application of the emulsion to a support.

In the present invention, an especially preferable result is obtained if pinakryptol yellow or pinakryptol green etc. which are known, is used as the desensitizer together with the above-described thallium compound and dye of the formula (I).

The silver halide direct reversal photographic sensitive materials of the present invention can be prepared by a process which comprises forming fog nuclei by exposing to light the emulsion obtained by carrying out conventionally used emulsifying treatment and physical ageing treatment or by adding a reducing agent, for example, formaldehyde, hydrazine and stannous salts to the emulsion, applying the emulsion to a suitable support for photographic sensitive materials, and drying.

Further, conventional photographic additives such as hardeners, for example, chromium alum, 2,4-dichloro-striazine compounds, aziridine compounds, epoxy compounds and mucohalogenic acids; surface active agents, for example, sodium polyalkylenesulfonate, saponin, etc.; plasticizers, for example, vinyl-type compounds such as polyalkyl acrylates and a copolymer of an alkyl acrylate and acrylic acid, polyalkylene oxides, etc.; and preservatives may be used. The silver halide direct reversal photographic sensitive materials of the present invention have a very high sensitivity and a large exposure tolerance as shown in the following examples.

The present invention will be explained in greater detail by reference to the following examples.

Example 1 To 800cc. of a 10% aqueous gelatin solution containing 0.3 g. of thallium nitrate, an aqueous solution containing 100 g. of silver nitrate and an aqueous solution containing 29 g. of sodium chloride and 16 g. of potassium bromide were added at the same time to form silver halide particles.

After the conclusion of the formation of the particles, 1 g. of potassium iodide and 40 g. of gelatin were added and the pH was adjusted to 9.5. After added 3 cc. of a 1% hydrazine hydrochloride, the emulsion was subjected to ripening for 40 minutes to form fog nuclei. After ripening the pH Was adjusted to 6.0- by adding an acid such as sulfuric acid, nitric acid or citric acid. This emulsion was designated Emulsion A.

As a comparison sample, an emulsion which did not contain thallium nitrate was prepared in the same manner as described above. This emulsion was designated Emulsion B.

To these emulsions, Dye A was added as in Table 1. In this case, pinacryptol yellow was partially used.

These emulsions were applied to cellulose acetate films and dried to produce silver halide direct reversal photosensitive elements. Using an optical wedge for sensitometry, these photographic elements were exposed to a 2660 K. tungsten lamp and developed at 20 C. for 5 minutes using a developer having the following composition.

Composition of Developer Metol 3 Hydroquinone 12 Sodium Sulfite 45 Sodium Carbonate 70 Potassium Bromide 2 Water to make 1000 cc.

TABLE 1 Amount added (mg/mol Ag) Emul- Thallium Pinacryptol Sample number sion nitrate Dye A yellow a 300 200 "an H In sample No. 7, 8 and 9, the thallium nitrate was added after the preparation of the emulsions and just before the application thereof to the support.

The results obtained are shown in Table 2.

Nora:

Relative speed: Relative speed values shown are on the assumption that the speed of Sample N o. 4 was 10.

Exposure tolerance: Difierence between the quantity of exposure of the positive image parts (log E1) which is (base density+fog density-l-density: 0.5) and the quantity of exposure of the negative image parts (loggEr) which is (base density+tog density+density: 0.5): that is the exposure tolerance is (log Ez-log E1).

It is clear from the results contained in Table 2 that Sample No. 2 and 3 have a high sensitivity and a wide exposure tolerance. It is also clear that samples to which thallium nitrate was added at a time other than at the formation of silver halide and during physical ripening, that is, just before application to a support, as in Sample No. 7, 8 and 9, exhibit poor sensitivity and exposure latitude in comparison with samples to which thallium nitrate is added at the formation of silver halide or physical ripening.

Example 2 To 800 cc. of a 10% aqueous gelatin solution containing 0.2 g. of thallium nitrate, an aqueous solution containing g. of silver nitrate and an aqueous solution containing 6 g. of sodium chloride, 65 g. of potassium bromide and 20 mg. of rhodium chloride were added at the same time to form silver halide particles.

After formation of the particles, 1 g. of potassium iodide and 40 g. of gelatin were added and the pH was adjusted to 9.5. To this emuslion, 5 cc. of a 1% hydrazine hydrochloride and 2 cc. of potassium chloroaurate were added to form fog nuclei. After this, the pH of the emul- TABLE 3 Amount added (mg/mol Ag) E mul- Pinacryptol sion Dye yellow C 300 200 D 200 D 300 6 D 300 200 7 B 200 The results obtained on evaluation are shown in Table 4.

TABLE 4 Relative Exposure Sample Number speed tolerance It is obvious from the results contained in Table 4 that Sample No. 2 and 3 have a clearly high sensitivity and a wide exposure latitude.

Example 3 TABLE 5 Amount added (mg/mol Ag) Sample Emul- Pinaeryptol number sion Dye C Dye K Dye N yellow TABLE 6 Relative speed Exposure latitude As is clear from the results contained in Table 6, Sample Nos. 2, 3, 8, 9, 14 and 15 have a high sensitivity and a wide exposure latitude.

While the invention has been described in detail and with reference to specific embodiment thereof, it will be apparent that various changes and modifications can be made therein without departing from the spirit and scope thereof.

What is claimed is:

1. A direct reversal photographic sensitive material which comprises a photographic emulsion containing fogged silver halide particles therein, at least one dye represented by the formula (I) wherein Z represents a group of atoms necessary to form a. cycloheptatriene ring, Z represents an oxygen atom or NH-, Z represents a group of atoms necessary to form a 5- or 6-member heterocyclic nucleus as is used in conventional cyanine dyes, R represents an alkyl group having from 1 to 6 carbon atoms or a substituted alkyl group having from 1 to 6 carbon atoms selected from the group consisting of a hydroxyalkyl group, an alkoxyalkyl group, a carboxyalkyl group, a sulfoalkyl group, a sulfatoalkyl group, an acetoxyalkyl group, an alkoxycarbonylalkyl group, a vinylalkyl group, an alkaryl group, a carboxyalkaryl and a sulfoalkaryl group, L and L each represents a methine group or substituted methine group where the substituent is an alkoxyalkyl or hydroxyalkyl group, L may form a methylene chain by linking to R, X represents an anion, and m and n represent each 0 or 1, and a thallium salt, said thallium salt being added to said emulsion during formation of said silver halide particles, during physical ripening of said emulsion, or during formation of said silver halide particles and during physical ripening of said emulsion, said dye being present in an amount effective to provide high reversal sensitivity and wide exposure latitude.

2. The direct reversal photographic sensitive material of Claim 1 wherein said emulsion contains pinacryptol yellow.

3. The direct reversal photographic sensitive material of Claim 1, wherein said cycloheptatriene ring is substituted by substituents selected from the group consisting of lower alkyl groups, halogen atoms, alkoxy groups and aryl groups.

4. The direct reversal photographic sensitive material of Claim 1, wherein said heterocyclic nucleus formed by Z; is an oxazoline nucleus, an oxazole nucleus, a benzoxazole nucleus, a naphthoxazole nucleus, a thiazoline nucleus, a thiazole nucleus, a benzothiazole nucleus, a naphthothiazole nucleus, a selenazole nucleus, a benzoselenazole nucleus, a naphthoselenazole nucleus, a Z-pyridine nucleus, a 4-pyridine nucleus, a Z-quinoline nucleus, a 4-quinoline nucleus, an imidazole nucleus, 3. benzoimidazole nucleus, a naphthoimidazole nucleus, an indolenine nucleus or an imidazole [4, 5, 6] quinoxaline nucleus.

5. The direct reversal photographic sensitive material of Claim 1, wherein said thallium salt is thallium sulfate or thallium nitrate.

6. The direct reversal photographic sensitive material of Claim 1, wherein said thallium salt is present in said emulsion at a level ranging from 1X 10- mol to 1X10- mol, based on the thallium, per mole of silver halide, and wherein said dye is present in said emulsion at a level ranging from 10 mg. to l g. per mole of silver halide.

7. The direct reversal photographic sensitive material of Claim 1, wherein said thallium salt is added during formation of said silver halide particles.

8. The direct reversal photographic sensitive material of Claim 1, wherein said thallium salt is added during physical ripening of said emulsion.

9. The direct reversal photographic sensitive material of Claim 1, wherein said thallium salt is added during formation of said silver halide particles and during physical ripening of said emulsion.

10. The direct reversal photographic sensitive material of Claim 1, wherein said Z heterocyclic nucleus is substituted by a member selected from the group consisting of an alkyl group, an aryl group, a hydroxyl group, an alkoxy group or a halogen atom.

11. The direct reversal photographic sensitive material of Claim 1, wherein said 5- or 6-member heterocyclic nucleus comprises one or more atoms selected from the group consisting of carbon, oxygen, sulfur, selenium and nitrogen.

12. The direct reversal photographic sensitive material of Claim 1, wherein said thallium salt is water soluble.

13. The direct reversal photographic sensitive material of Claim 1, wherein the amount of thallium salt is from 1X 10- to 1 10 moles as thallium per mole of silver halide and the amount of dye represented by general formula (I) is from to 500 mg. per mole of silver halide.

References Cited UNITED STATES PATENTS RONALD H. SMITH, Primary Examiner W. H. LOUIE, JR., Assistant Examiner US. Cl. X.R. 

